HYDRAULICS & MARITIME RESEARCH CENTRE Concepts and Science for Concepts and Science for Coastal Erosion Management Coastal Erosion Management Jeremy Gault Jimmy Murphy Anne Marie O’Hagan Val Cummins Inch Beach – Pilot Site 27th April 2009
Pilot Site Inch Beach Inch Beach – Location
Pilot Site Inch Beach Frame of Reference - application STRATEGIC OBJECTIVE: STRATEGIC OBJECTIVE: To provide for proper planning & sustainable development To provide for proper planning & sustainable development OPERATIONAL OBJECTIVE: OPERATIONAL OBJECTIVE: Prevent damage to infrastructure Prevent damage to infrastructure 2. Evaluation: 4. Evaluation: 1. Quantitative state 2. Benchmark 1. Intervention: 3. Intervention: Perceived success of Perceived success of concept Protective measures Protective measures protective measures protective measures I n reality the CSI for I nch is a catastrophic event (or the political / CSIs CSIs Favourable Sediment Status public outcry that accompanies the Monitoring Monitoring System knowledge System knowledge event) rather than the response to a Measurement Measurement Current Sediment Status routine physical measurement Modelling Modelling (monitoring campaign).
Pilot Site Inch Beach Inch Beach – Background • length: 5.5 km • large barrier-dune system • dissipative shore-face (slope 1:100 nearshore) • spring tidal range 3.2 m • embayment (30 km 2 ) constrained by resistant headlands • fixed sediment volume • ebb tidal delta: sink and source of sediment
Pilot Site Inch Beach Inch Beach – Activities • Introduction of the frame of reference and problem description • Delineation and quantification of coastal cells • Data set inventory (active) • Extreme wave analysis • Input 40 year time series (WAM generated) • Series of post storm coastline position / topographic surveys • Sediment grain size analysis • Wave modelling with MIKE21 • Input from 40 year time series • Calibration from in-situ wave gauges • Map derived bathymetry • Simulation of storm episodes • Modelling of erosion processes nearshore (LITPACK) • Input from MIKE21 model • [Ongoing analysis of historical change (using GIS)]
Pilot Site Inch Beach Inch Beach – Frame of Reference How it contributes to the Process Description The real-time wave data confirms the high energy nature of this system and this is backed by the sediment data which shows a largely uniform sediment type. The derived modelling data supported by the field GPS surveys has confirmed that the beach is eroded routinely under large storm conditions. However it tends to recover quickly even when several metres of coastline are lost to erosion. Sediment taken offshore is quickly re-deposited and subsequently colonised to replace lost dune structure. The sediment models appear to support this with the cross-shore transport being the pre-dominant direction of sediment movement. This all tends to support the literature collated which suggests that Inch only suffers larger scale erosions (100’s of metres) during extreme conditions. The Functions Affected (Problem Description) As the main issue is protection of infrastructure / safety of life it would appear that the problem is being addressed. However at this site there is no monitoring and assessment of the four key erosion concepts is difficult as there is no driver (policy) and therefore no resources to carry out the research necessary to develop accurate physical CSI’s. In terms of the frame of reference end-users see themselves as going from Operational Objective straight to Intervention.
Pilot Site Inch Beach Frame of Reference STRATEGIC OBJECTIVE: STRATEGIC OBJECTIVE: To provide for proper planning & sustainable development To provide for proper planning & sustainable development OPERATIONAL OBJECTIVE: OPERATIONAL OBJECTIVE: Prevent damage to infrastructure Prevent damage to infrastructure 2. Evaluation: 4. Evaluation: 1. Quantitative state 2. Benchmark 1. Intervention: 3. Intervention: Perceived success of Perceived success of concept Protective measures Protective measures protective measures protective measures I n reality the CSI for I nch is a catastrophic event (or the political / CSIs CSIs Favourable Sediment Status public outcry that accompanies the Monitoring Monitoring System knowledge System knowledge event) rather than the response to a Measurement Measurement Current Sediment Status routine physical measurement Modelling Modelling (monitoring campaign).
Pilot Site Inch Beach Frame of Reference - Real Institutional Framework STRATEGIC OBJECTIVE: To provide for proper planning & sustainable development National Government implemented by Local Government (Planning & development Act, 2000; Foreshore Acts, 1933-2005; Coastal Protection Act, 1963 and associated Regulations) OPERATIONAL OBJECTIVE: Prevent damage to infrastructure Kerry County Council National Government implemented by Local Government (Planning & development Act, 2000; Foreshore Acts, 1933-2005; 2. Evaluation: Coastal Protection Act, 1963 and associated Regulations) 1. Intervention: Perceived success of Protective measures protective measures Kerry County Council Kerry County Council Need for integrated dedicated Act or Policy, current legislation is contradictory & therefore subject to interpretation (abuse?).
Pilot Site Inch Beach Frame of Reference - Idealised Institutional Framework STRATEGIC OBJECTIVE: To provide for proper planning & sustainable development National Government implemented by Local Government Implementation of existing relevant policy and review of contradictory Acts to create a new piece of legislation OPERATIONAL OBJECTIVE: Prevent damage to infrastructure Kerry County Council 4. Evaluation: 1. Quantitative state 2. Benchmark 3. Intervention: Perceived success of concept National Government Protective measures protective measures Kerry County Council (through regional office) Kerry County Council National Government Delineate Sediment Cell (through regional office) Identify Strategic Sediment Reservoir CSIs Favourable Sediment Status Monitoring System knowledge Measurement Current Sediment Status Modelling
Pilot Site Inch Beach Inch Beach – Recent developments
Pilot Site Inch Beach Inch Beach – Recent developments
Pilot Site Inch Beach Inch Beach – Recent developments
Pilot Site Inch Beach Inch Beach – Recent developments
Pilot Site Inch Beach Inch Beach – Recent developments
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